Tool and method to create an accurate cast of the internal form of a component

ABSTRACT

A molding tool ( 10 ) has a body ( 20 ) that can be inserted into a cavity ( 62 ) of a component ( 12 ) for introducing molding material ( 72 ) to form a mold of one or more internal surfaces ( 60 ) defining the cavity ( 62 ). The molding material ( 72 ) is at least partially cured with the tool ( 10 ) in place so that the mold ( 80 ) and tool ( 10 ) are removed from the cavity ( 62 ) as a single unit. The tool ( 10 ) includes a passage ( 34 ) for introducing the molding material ( 72 ) into the cavity ( 62 ). A pressure device, such as a plunger ( 50 ), may be used to force the molding material ( 72 ) through the passage ( 34 ) and into the cavity ( 62 ). The tool ( 10 ) also serves to support the mold ( 80 ) on a fixture or other structure used to analyze the mold ( 80 ) to verify characteristics of the form, such as, for example, an optical comparator.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/378,080 filed on May 15, 2002 for FEMALE FORM MOLD TOOL AND METHOD,the entire disclosure of which is fully incorporated by reference.

BACKGROUND OF THE INVENTION

Many industrial components include internal openings, such as a cavityor bore or recessed volume, defined by an internal form (internalsurface) of the component The internal form may include various surfaceportions, such as threads or angles or radii. In some cases it isimportant to be able to measure very accurately the configuration ofsome or all of the surface portions, or to be able to compare them witha predetermined template to check them for accuracy.

For example, the internal form of the component may include femalethreads configured to receive external male threads on another componentof a connecting or coupling system. For such a connecting or couplingsystem to operate effectively, the threads present within the femalecomponent are manufactured to meet certain specifications and tolerancesor to have certain characteristics. Verifying that a female threadedcomponent actually possesses certain characteristics often requires areplica mold or cast of the threads to be made after the component hasbeen manufactured. The analysis is accomplished by placing the mold orcast on an optical comparator or other suitable device. (The terms“mold” and “cast” are used interchangeably herein.)

Creating the mold or cast of an internal form (whether threaded orunthreaded) can be a difficult and laborious process that results inpartial or incomplete molds and wasted molding material. Providingpositional stability to a mold that has been placed in an opticalcomparator is also frequently problematic because the molding or castingmaterial is typically a relatively soft and flexible material.Inaccurate comparison data may result if a mold is not stable on thecomparator while the analysis is being conducted.

Thus, there is a need for apparatus and methods that consistentlyproduce accurate molds of the internal form of a component and that alsoprovide an arrangement for mounting and immobilizing the mold on anoptical comparator or other test equipment for analysis.

SUMMARY OF THE INVENTION

The invention relates to apparatus and methods for making a replica moldor casting of a form that defines an internal cavity of a component Inone embodiment, the invention is realized in the form of a tool having abody that can be at least partially inserted into the cavity of thecomponent for introducing a molding material therethrough. The moldingmaterial is at least partially cured with the tool in place so that themold and tool are removed from the component as a single unit. Anapplication of the invention is for making a mold of a female threadstructure within a female nut of a coupling. The finished mold and toolare removed by unscrewing the tool from the component. The tool includesa passageway for introducing the molding material into the internalcavity of the female component, and a pressure device, for example, aplunger, may be used to force the molding material through thepassageway and into the cavity. In accordance with another aspect of theinvention, the mold tool provides a convenient structure for supportingthe mold on a fixture or other structure used to analyze the mold toverify characteristics of the form, such as, for example, an opticalcomparator.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing and other features of the present invention will becomeapparent to one skilled in the art to which the present inventionrelates upon consideration of the following description of the inventionwith reference to the accompanying drawings, in which:

FIG. 1 is an elevational view of a molding tool in accordance with afirst embodiment of the present invention, the molding tool includingboth a mold template and a plunger,

FIG. 2 is a perspective view of the mold template of FIG. 1;

FIG. 3 is a sectional view of the mold template of FIG. 1, taken alongline 3-3 of FIG. 1;

FIG. 4 is an elevational view, partially in section, showing the moldingtool of FIG. 1 in use for making a mold of an internal form of acomponent;

FIG. 5 is a schematic view illustrating the supporting of the moldtemplate of FIG. 1 with the mold thereon for analysis by an opticalcomparator,

FIG. 6 is a sectional view similar to FIG. 3 of the mold template withthe mold thereon, taken along line 6-6 of FIG. 5;

FIG. 7 is a view similar to FIG. 1 of a molding tool in accordance witha second embodiment of the present invention, the molding tool includinga threaded plunger,

FIGS. 8 and 9 are views of a molding tool in accordance with a thirdembodiment of the invention, shown in use for making a mold of anon-threaded cavity in a component;

FIGS. 10 and 11 are views of a molding tool in accordance with a fourthembodiment of the invention, shown in use for making a mold of alongitudinal portion only of a deep cavity in a component;

FIGS. 12-17 are a series of views of a molding tool in accordance with afifth embodiment of the invention, shown in use for making a mold of acircumferential portion only of a cavity in a component;

FIG. 18 is a view of a molding tool in accordance with a sixthembodiment of the invention, including a dispenser for a two partmolding material; and

FIG. 19 is a view of a molding tool in accordance with a seventhembodiment of the invention, in which the mold template has amulti-piece construction.

DETAILED DESCRIPTION

The present invention provides a device or tool for creating an accuratecast or mold of the internal form of a component This mold may be usedto inspect and verify the characteristics, including dimensions, of theinternal form of the component. This invention also provides anarrangement for mounting and immobilizing the mold on an opticalcomparator or other equipment for analysis. The invention is applicableto various devices or tools for determining whether a part has beenmanufactured to specification.

The present invention may be readily applied to produce molds of a widevariety of internal forms in a component having an internal geometry,including but not limited to threads, tapers, chamfers, counter bores,recesses and so on, to name a few examples.

As representative of the invention, FIG. 1 illustrates a tool 10constructed in accordance with a first embodiment of the invention. Thetool 10 is specifically adapted for making a mold of an internallythreaded component 12 (FIG. 4).

The tool 10 includes a mold template 20 and a pressure member or plunger50. The mold template 20 (FIGS. 1 and 2) is preferably formed as onepiece. The material of the mold template 20 is selected so that the moldtemplate is rigid. Thus, the mold template 20 is firm enough so that itcan be placed in or on an optical comparator or other analyticalinstrument and held in place so that a mold that is on the mold template20 is supported in a stable manner and can be properly analyzed by theinstrument.

The mold template 20 includes a first collar 22, a molding cylinder 24and an end cap 26. The first collar 22 has a generally cylindricalconfiguration centered on a longitudinal central axis 28 of the moldtemplate 20. The first collar 22 has an inner side surface 30.

The first collar 22 is preferably greater in diameter than the moldingcylinder 24 and is adapted to be easily grasped by the hand of anoperator to remove the mold template 20 from association with thecomponent that is being analyzed The first collar 22 may also includewrenching flats (not shown) for rotating the mold template 20 about theaxis 28 with the aid of a tool, such as a wrench.

The molding cylinder 24 is a generally cylindrical body that extendsaxially from the the first collar 22. The molding cylinder 24 has acylindrical outer surface 32 centered on the axis 28.

A central bore or passage 34 of the mold template 20, defined by acylindrical surface 36, extends completely through the first collar 22and through roughly three-fourths the length of the molding cylinder 24.The passage 34 is closed by the inner end of the molding cylinder 24.

The outer end of the passage 34 terminates in a chamfer 38 in the firstcollar 22. The chamfer 38 is centered on the axis 28. The chamfer 38 maybe used to help support the mold template 20 on an optical comparator orother analytical device or equipment, for example, in a manner describedbelow.

The end cap 26 is disposed at the end of the molding cylinder 24opposite the first collar 22. The end cap 26 is slightly greater indiameter than the molding cylinder 24. The end cap 26 is dimensioned tobe just small enough to enter the cavity being molded.

A notch 40 is formed in the radially extending outer end surface of theend cap 26. The notch 40 is located on the axis 28. The notch 40 may beused to help support the mold template 20 on an optical comparator orother analytical device or equipment, for example, in a manner asdescribed below.

The mold template 20 includes a retaining and positioning ring 42 thatencircles the molding cylinder 24 at the point where the moldingcylinder extends from the first collar 22. The ring 42 is roughly equalin diameter to the diameter of the end cap 26. Thus, in a preferredembodiment, the diameter of the molding cylinder 24 is slightly lessthan the diameters of the ring 42 and of the end cap 26. Thisconfiguration provides a means for retaining molding material inside thecavity being molded, thereby reducing the tendency of the moldingmaterial to escape or leak out of the thread component. The ring 42 andthe cap 26 act as dams to resist flow of the molding material outsidethe form volume being molded and also to help ensure flow of thematerial into all the spaces of the form.

The molding cylinder 24 further comprises one or a plurality of flatsurfaces 44. In a preferred embodiment of this invention, three flatsurfaces 44 are provided on the molding cylinder 24, spaced apart at120° intervals about the axis 28. The flat surfaces 44 are preferably,but not necessarily, located near the inner end of the molding cylinder24.

Three radial passages 46 extend between the central passage 34 of themold template 20 and the flat surfaces 44. The radial passages 46terminate in respective apertures 48 formed in the flat surfaces 24.Preferably, each aperture 48 is centrally positioned, lengthwise andwidthwise, on its associated flat surface 44.

The pressure member 50 is a component that may be used to apply pressureto molding material, as described below, to squeeze molding materialthrough the passage 34 and out the apertures 48. The pressure member 50may therefore take on many configurations other than those illustratedherein. In the embodiment in FIGS. 1-6, the pressure member 50 is adevice that is separate and distinct from the mold template 20. In otherembodiments, the pressure member 50 may be a component that is notphysically separate from the template 20, or may be a separate componentthat is attached. The pressure member 50 is preferably but notnecessarily manufactured from the same material as the mold template 12,such as nylon or other suitable materials.

The pressure member 50 that is shown in FIGS. 1 and 4 is a plunger. Theplunger 50 includes a main body portion 52 having an elongatecylindrical configuration with a diameter slightly less than that of thecentral bore 34 of the template 20. The plunger 50 preferably furtherincludes at its outer end a second collar 54 which may be easily graspedby hand of an operator to depress and retract the plunger 50. The secondcollar 54 of the plunger 50 is larger in diameter than the main bodyportion 52.

In the embodiment illustrated in FIGS. 1-6, the component 12 to beanalyzed (FIG. 4) is a coupling part having an internal threadconvolution 60 defining a cavity 62 of the component. The component 12also has an outer end face 64 and an inner end face 66 at opposite endsof the cavity 62. The component 12 further has a fluid passage 68extending from the inner end face 66 in a direction away from the cavity62. The thread convolution 60 has crests, troughs, a pitch, etc. Themolding tool 10 may be used in the following manner to analyze thethread convolution 60 of the component 12 to determine whether it hasbeen manufactured to specification.

In operation, the molding cylinder 24 of the mold template 20 isinserted into the cavity 62 of the component 12, as shown in FIG. 4. Theinner side surface 30 of the first collar 22 preferably but notnecessarily engages the outer end face 64 of the component 12. The endcap 26 preferably engages the inner end face 66 of the component As aresult, the mold template 20 at least partially closes the cavity 62.The molding cylinder 24 is spaced radially inward a small amount fromthe thread convolution 60, thus defining an annular molding cavity orspace 70.

An appropriate quantity of molding material 72 is inserted in thecentral bore 34 of the mold template 20 through the end of the passage34 in the first collar 22. A preferred molding material 72 isREPRORUBBER brand molding material. This material 72 is available fromFlexbar Machine Corp. of Central Islip, N.Y. Other molding materials 72are usable. The preferred molding material 72, when cured, is generallynot rigid enough to support itself in a stable manner as needed foranalysis on an optical comparator.

It may be feasible to use the passage 34 in the mold template 20 tomeasure the appropriate quantity of molding material 72. To do this, thesize of the passage 34 would be selected to provide the correct amountof molding material 72 for the mold to be cast in that particularoperation. Appropriate quantity markers could be placed on the mold tool10. Controlling the quantity of molding material 72 that is used isespecially desirable when a mold is to be made of only a limited portionof a cavity, as discussed below, for example, with reference to FIGS.12-17.

The main body portion 52 of the plunger 50 is inserted at leastpartially into the central bore 34 of the mold template 20. Pressure ismanually applied to the molding material 72 by pushing axially on theplunger 50. The force applied to the plunger 50 causes the moldingmaterial 72 to flow axially through the central bore 34 into the radialpassages 46 in the mold template 20 and radially out the apertures 48.The molding material 72 enters the annular space 70 between the moldtemplate 20 and the thread convolution 60. The plunger 50 is dimensionedto be a close fit in the mold template 20, to prevent molding material72 from coming back out around the plunger.

The recessed flat surfaces 44 provide additional open space to help themolding material 72 to flow from the molding cylinder 24 into themolding space 70. The molding material 72 also flows into the formvolume such as the spaces between adjacent threads of the threadconvolution 60 component. Sufficient pressure is applied to force themolding material 72 completely into all the spaces and against all thesurfaces that define the cavity 62 of the component 12. A substantialamount of pressure may be needed to force out any air from the cavity 62and the molding material 72. Excess air in the cavity 62 is ventedaround the diametrical clearance between the molding tool 10 and thepart 12 being molded.

The molding material 72 is forced into intimate contact with theinternal form of the component 12. Sufficient time is allowed for themolding material 72 to fill all the desired spaces. A mold 80 is formedhaving an outer surface 82 that is an exact replica of the inner surfaceof the component 12.

After a period of time sufficient for the molding material 72 to hardenor at least partially cure or solidify enough for removal withoutaltering the shape of the mold 80, the mold template 20 is removed fromthe component 12 by grasping the first collar 22 and unscrewing the moldtemplate (FIG. 3). The molding material 72 releases from the component12 but sticks to the mold template 20, and so the mold 80 comes out ofthe cavity with the mold template. The presence of cured moldingmaterial 72 in the radially extending passages 46 helps to interlock themold 80 and the mold template 20. In addition, the flat surfaces 44 onthe mold template 20 act as bearing surfaces that transmit therotational force of the mold template 20 to the mold 80, better than acylindrical surface would do, to help rotate the mold relative to thecomponent 12. The plunger 50 may be removed before or after the moldtemplate 20 is removed from the component 12.

The resulting assembly is shown in FIGS. 5 and 6 and includes the moldtemplate 20 and the mold 80. The mold 80 has an annular (hollow)configuration extending 360 degrees around the molding cylinder 24 ofthe mold template 20. The exterior surface 82 of the mold 80 is an exactreplica of the internal surface of the component 12. In this case, themold 80 has an external thread convolution 84 that replicates theinternal thread convolution 60 of the component 12. The external threadconvolution 84 is visible on the exterior of the mold template 20. Thus,an accurate, measurable mold or replica of the interior threads of thefemale thread component 12 is present on the exterior of moldingcylinder 24.

The finished mold 80, to be analyzed, is placed on an optical comparatoror other equipment as illustrated schematically at 86 in FIG. 5. Themold 80 is supported on the comparator 86 by the mold template 20. Themold template 20 is supported in position on the comparator 86 bycenters 88 and 90. The center 88 engages in the chamfer 38 on the firstcollar 22 of the mold template 20. The center 90 engages in the notch 40in the end cap 26 of the mold template 20.

Because the mold template 20 is a rigid member, the mold template issupported firmly in position on the optical comparator 86. As a result,the mold 80, itself, is firmly and in a stable manner supported inposition on the optical comparator 86 so that a proper analysis of theexternal thread convolution 84 can be made. For example, the assembly ofthe mold template 20 and the mold 80 can be accurately positioned within1/1000 of an inch on the comparator 86. This is often not possible withan unsupported plug of cured molding material 72. Many other supportingarrangements for the completed mold 80 are possible and will be readilyapparent to those skilled in the art. For example, rather than a notchor chamfer, a raised boss may be provided on the mold template 20 forclamping in a fixture. In addition, the plunger 50 may be left in themold template 20, and the plunger used to help support the mold 80 inthe analyzing device.

Advantageously, the tool 10 may be reused, as the mold 80 simply peelsaway from the cylinder 24 after the analysis is completed. In addition,because the molding cylinder 24 is located within the mold 80, the moldis only a relatively thin walled cylinder of molding material 72 ratherthan a solid plug of molding material. This reduces usage of theexpensive molding material 72.

By way of example and not limitation, the diameter of the ring 42 andthe diameter of the end cap 26 may be the same as each other, and may beslightly smaller than the part being measured, for example about 0.02inches smaller for small parts and about 0.04 inches for larger parts.The diameter of the cylinder 20 may be about 0.04 inches smaller thanthe diameters of the ring 42 and the end cap 26.

Still further by way of example, the total length represented by thering 42, the cylinder 24 and the end cap 26 may be about 0.03 inchesshorter than the depth of the cavity being measured for small parts andabout 0.06 inches shorter than the cavity being measured for largerparts. As used herein and still by way of example, a “small” part may bea part such as a ¼ inch fitting and under and a “larger” part may be apart such as an over ¼ inch fitting.

In the embodiment of FIGS. 1-6, the mold 80 is formed with the template20 in place so as to facilitate removal of the mold after cure. However,it is possible to remove the template 20 if required as soon as themolding material 70 has been introduced into the component 12. In such acase the finished mold 80 can still be unscrewed from the component 12but might not be as rigidly supported for the test equipment.

Both the mold template 20 and the plunger 50 are scalable, meaning thateach may be adapted to a variety of dimensional requirements. Forexample, to mold the threads of a female thread component having asmaller internal diameter, the molding cylinder may be made smaller.

FIG. 7 illustrates a molding tool 110 a constructed in accordance with asecond embodiment of the invention. The molding tool 110 a is similar inconstruction to the molding tool 10 (FIGS. 1-6), and parts that are thesame or similar are given the same reference numerals with the suffix“a” attached

The molding tool 10 a (FIG. 7) includes a plunger 50 a having anexternal thread convolution 51 on the main body portion 52 a of theplunger. The mold template 20 a includes an internal thread convolution21 along a portion of the length of its central passage 34 a.

The plunger 50 a can, as a result, be screwed into the mold template 20a during introduction of molding material, rather than being pushed inwithout rotating as in the first embodiment. The mechanical advantage ofthe screw threaded connection between the plunger 50 a and the moldtemplate 20 a can help the operator apply more pressure duringintroduction of molding material. This can help to ensure that themolding material is moved into intimate contact with all portions of theinternal form to be analyzed.

FIGS. 8 and 9 illustrate a molding tool 10 b constructed in accordancewith a third embodiment of the invention. The molding tool 10 b issimilar in construction to the molding tool 10 (FIGS. 1-6), and partsthat are the same or similar are given the same reference numerals withthe suffix “b” attached.

The molding tool 10 b (FIGS. 8 and 9) is adapted for use in producing amold of a cavity 62 a in a component 12 a. The cavity 62 a has anon-cylindrical configuration as defined by a tapering surface 90, acylindrical surface 92, and another tapering surface 94. The cavity 62 ais not internally threaded; the invention is applicable to the moldingof replicas of non-threaded cavities in addition to the molding ofthreaded cavities as shown in FIGS. 1-6.

The mold template 20 b (FIG. 8) has a configuration complementary tothat of the cavity 62 a. Thus, the mold template 20 b has an externalsurface including a tapering surface 96, a cylindrical surface 98, andanother tapering surface 100. The mold template 20 b includes an axiallyextending central passage 34 b for the introduction of molding material72 a into the cavity 62 a in the component 12 a.

The central passage 34 b opens into three radially extending passages 46b in the mold template 20 b. The passages 46 b are spaced axially alongthe length of the mold template 20 b, at locations that are adjacent thecomponent surfaces to be replicated when the mold template is inposition in the cavity 62 a. As a result, the molding material 72 a(FIG. 9), when forced into the cavity 62 a by the plunger 50 b, isforced radially outward to the desired locations in the cavity againstthe surfaces 90, 92 and 94.

The mold template 20 b has a tip 102 that engages the component 12 a.This engagement blocks flow of molding material 72 a into the inner endportion of the cavity 62 a and also centers and stabilizes the moldtemplate 20 b in the cavity.

FIGS. 10 and 11 illustrate a molding tool 10 c constructed in accordancewith a fourth embodiment of the invention. The molding tool 10 c issimilar in construction to the molding tool 10 (FIGS. 1-6), and partsthat are the same or similar are given the same reference numerals withthe suffix “c” attached.

The molding tool 10 c (FIGS. 10 and 11) is adapted for use in producinga mold of a specific longitudinal portion only of a deep cavity 110 in acomponent 112. Other tools can be constructed in accordance with theinvention for molding at a particular depth along the length of acavity, or for molding more deeply in a cavity than, for example, themold tool of FIG. 1.

The cavity 110 has a two-part cylindrical configuration including alarger diameter outer chamber section 114 and a smaller diameter innerchamber section 116. In the illustrated embodiment, the inner chambersection 116 is to be molded for analysis. The inner chamber section 116may be more than halfway into the overall cavity 110. The inner chambersection 116 may be, for example, the deepest 10% or 20% of the overallcavity 110.

The mold template 20 c has a configuration complementary to that of thecavity 110. Specifically, the mold template 20 c has a relatively longouter portion 120 with a cylindrical configuration. A shorter innerportion 122 of the mold template 20 c extends from the outer portion120. The inner portion 122 has a cylindrical configuration and issmaller in diameter than the outer portion 120.

The mold template 20 c includes an axially extending central passage 34c for the introduction of molding material 72 c into the cavity 110 inthe component 112. The central passage 34 c opens into two radiallyextending ports or apertures 48 c in the mold template 20 c. Theapertures 48 c are located circumferentially opposite each other on theinner portion 122 of the mold template 20 c. The mold template 20 c alsoincludes a circumferential seal 124 located on the inner portion 122above (outward of) the apertures 48 c.

The molding material 72 c (FIG. 11), when forced into the cavity 110 bythe plunger 50 c, is forced radially outward through the apertures 48 cto the desired locations in the cavity. The seal 124 blocks axiallyoutward flow of the molding material 72 c. The engagement of the tip ofthe mold template 20 c with the component 112 blocks axially inward flowof molding material 72 c. As a result, the molding material 72 c istrapped axially between the seal 124 and the mold template tip, forforming a mold 80 c of a portion of the inner chamber section 116 butnot the outer chamber section 114.

When the mold 80 c is at least partially cured, the mold template 20 ccan be removed from the cavity 110 in the component 112, bringing themold with it. The mold 80 c is securely supported on the rigid moldtemplate 20 c and thus is suitable for imaging on, for example, anoptical comparator.

FIGS. 12-17 illustrate a molding tool 10 d constructed in accordancewith a fifth embodiment of the invention. The molding tool 10 d (FIGS.10 and 11) is adapted for use in producing a mold 80 d of acircumferential portion only, less than 360 degrees, of a cavity 130 ina component 132. Other molding tool configurations are possible formolding a limited circumferential portion of a cavity.

The cavity 130 (FIG. 12) has an undercut, cylindrical configuration,including a smaller diameter outer chamber section 134 defined by asurface 144 and a larger diameter inner chamber section 136 defined by asurface 138. In the illustrated embodiment, a portion of the innerchamber section 136 is to be molded for analysis. Because the chamberportion 136 to be molded is undercut, it would be difficult orimpossible to mold (replicate) the entire inner chamber portion andremove the mold from the cavity. Therefore, only a portion of thecylindrical surface 138 defining the inner chamber portion 136 ismolded, as described below.

The molding tool 10 d includes a mold template 20 d and a plunger 50 d.The molding tool 10 d also includes a wedge 140 for helping to positionthe mold template 20 d in the cavity 130.

The mold template 20 d has a cylindrical outer surface 142 forengagement with the surface 144 defining the outer chamber section 134of the cavity 130. The mold template 20 d also has a planar wedgesurface 146 opposite the cylindrical surface 144. The mold template 20 dis sized so that it fills only a portion of the cavity 130 in thecomponent 132. A central passage 34 d in the mold template 20 dcommunicates with an opening 148 in the cylindrical outer surface 142adjacent the lower end of the mold template. The opening 148 extends foronly a portion of the circumferential extent of the mold template 20 d.In the illustrated embodiment, the opening 148 extends for about sixtydegrees.

The wedge 140 has a configuration complementary to that of the moldtemplate 20 d. The wedge 140 is sized and configured so that it fitsinto the portion of the cavity 130 not filled by the mold template 20 d.The wedge 140 has a cylindrical side surface 150 and a planar wedgesurface 152. The wedge 140 has a handle 154 on its outer end formanipulation of the wedge.

The molding tool 10 d is used by first inserting the mold template 20 dinto the cavity 130, as shown in FIG. 13, until it either bottoms out oris at the appropriate depth. The wedge 140 is then inserted adjacent themold template 20 d. The wedge surface 152 on the wedge 140 engages thewedge surface 146 on the mold template 20 d. The cylindrical surface 142on the wedge 140 engages the cylindrical surface 144 defining the outerchamber portion 134 on the component 132.

As the wedge 140 moves farther down into the cavity 130, the wedgeforces the mold template 20 d to move radially (sideways) against thecylindrical surface 144 defining the outer chamber portion 134 on thecomponent 132, as shown in FIG. 14.

The molding material 72 d (FIG. 14) is then introduced into the cavity130 through the central passage 34 d in the mold template 20 d. Theplunger 50 d is used to force the molding material 72 d out the opening148 into the inner chamber portion 136. The molding material 72 d flowsradially outward into intimate contact with the cylindrical surface 138defining the inner chamber portion 136. The amount of molding material72 d used is intentionally limited so that only a circumferentialportion, not all, of the inner chamber portion 136 is molded.

When the molding material 72 d is at least partially cured, the wedge140 is removed from the cavity 130 in the component 132, by lifting onthe handle 154, as shown in FIG. 15. When the wedge 140 is thus out ofthe cavity 130, the mold template 20 d, with the mold 80 d attached, ismoved sideways in the cavity, as shown in FIG. 15, so that the mold isno longer in the undercut area. The mold template 20 d, with the mold 80d attached, is then lifted out of the cavity 130, possibly by using theplunger 50 d as a handle, as shown in FIG. 16. The mold 80 d assupported on the mold template 20 d may then be analyzed.

FIG. 18 illustrates a molding tool 10 e in accordance with a sixthembodiment of the invention, for use with a two-part molding material.The two-part molding material is provided by a plunger 50 e. The plunger50 e has first and second chambers 164 and 166 separated from eachother. The two chambers 164 and 166 come together in a tip 162 which hasan outlet 168.

The two parts of the molding material are placed in the two chambers 164and 166, respectively, plunger 50 e. A pressure source indicatedschematically at 170 applies pressure simultaneously to both chambers164 and 166. The two parts of the molding material are forced into thetip 162 where they commingle. The resulting molding material is forcedout of the tip 162 into a mold template 20 e. In FIG. 18, the moldtemplate 20 e shown is similar to the mold template 10 (FIG. 1-6). Othermold templates may be used.

FIG. 19 illustrates a molding tool 10 f in accordance with a seventhembodiment of the invention, in which the mold template 20 f has amulti-piece construction. The molding tool 10 f is shown as being usedto mold a tapered, internally threaded, surface 170 of a component 172,such as a female pipe thread. The molding tool 10 f can be used to moldother types of surfaces, or other types of threads, and other moldingtools in accordance with the invention can be used to mold this type ofsurface.

The mold template 20 f includes a main body portion 174 having acylindrical configuration. A first section 176 of the main body portion174 has a cylindrical outer side surface 178. An outer section 180 ofthe main body portion 174 projects outward from the first section 176.The outer section 180 is smaller in diameter than the first section 176.Part of the outer section 180 is externally threaded and part has asmooth cylindrical configuration that forms an annular recess or groove182. At its opposite end, the main body portion 174 has a reduceddiameter annular recess or groove 184.

The main body portion 174 of the mold template 20 f is provided with acentral passage 34 f for the introduction of molding material into thecavity 185 of the component 172. The central passage 34 f extendscompletely through the main body portion 174 of the mold template 20 f.The passage 34 f is internally threaded at the inner end portion 186 ofthe main body portion 174. The molding tool 10 f also includes an endplug 188. The end plug 188 is adapted to screw into the internallythreaded inner end portion 186 of the main body portion 174 of the moldtemplate 20 f.

The molding tool 10 f also includes an inner ring 190. The inner ring190 is adapted to fit into the inner recess 184 in the main body portion174 of the mold template 20 f, and to engage the internal threadconvolution 170 on the component 172. The inner ring 190 acts tostabilize and center the mold template 20 f in the cavity 185.

The inner ring 190 may be made from a rigid material, such as metal. Inthis case, the inner ring 190 may be selected from a group of innerrings of different outer diameters. As a result, the inner ring 190 isadapted to engage internal surfaces of different diameters. The innerring 190 may, alternatively, be made from a flexible material, such asrubber. In this case, the inner ring 190 can be compressed to vary itsdiameter to enable it to engage internal surfaces of differentdiameters.

The molding tool 10 f also includes an outer ring 192. The outer ring192 is adapted to fit into the outer recess 182 in the main body portion174 of the mold template 20 f, and to engage the internal threadconvolution 170 on the component 172. The outer ring 192 thus acts tohold the molding material in the cavity 185 and to stabilize and centerthe mold template 20 f in the cavity.

The outer ring 192 may be made from a rigid material, such as metal. Inthis case, the outer ring 192 may be selected from a group of outerrings of different outer diameters. As a result, the outer ring 192 isadapted to engage internal surfaces of different diameters. The outerring 192 may, alternatively, be made from a flexible material, such asrubber. In this case, the outer ring 192 can be compressed to vary itsdiameter to enable it to engage internal surfaces of differentdiameters. In the illustrated embodiment, the outside diameter of theouter ring 192 is larger than the outside diameter of the inner ring190. This size difference enables the mold template 20 f to fit closelywithin the tapered cavity 185.

The main body portion 174 of the mold template 20 f includes one or moreradial passages 194 that enable flow of molding material from thecentral passage 34 f into the cavity 185. When the plunger (not shown)is inserted into the mold template 20 f, the molding material is forcedthrough the central passage 34 f and out the radial passages 194, intointimate contact with the internal surface 170 on the component 172. Theend plug 188 blocks flow of molding material out of the inner endportion 186 of the central passage 34 f. The inner and outer rings 190and 192 block flow of molding material out of the cavity 185.

After the molding material is cured or at least partially cured, themold template 20 f with the mold thereon is removed from the cavity 185by unscrewing. The mold 80 f can then be analyzed, supported on the moldtemplate 20 f. After the mold 80 f has been analyzed, it can be strippedoff the mold template 20 f, and the mold template can be reused,possibly with different sized inner and outer rings 190 and 192.

From the above description of the invention, those skilled in the artwill perceive improvements, changes, and modifications in the invention.Such improvements, changes, and modifications within the skill of theart are intended to be included within the scope of the appended claims.

1-40. (canceled)
 41. A method of making a cast of an internal form thatat least partially defines a cavity in a component, said methodcomprising the steps of: providing a molding tool having a molding bodywith a passage extending through the molding body; inserting a firstportion of the molding body into the cavity, wherein a second portion ofthe molding body is at least partially outside of the cavity;introducing a molding material through the passage into the cavity whilethe first portion of the molding tool is in the cavity; and at leastpartially curing the molding material to form a cast; removing themolding body and cast from the cavity without disassembling the moldingbody.
 42. The method of claim 41 wherein said step of at least partiallycuring the molding material includes adhering the molding material tothe molding tool, and wherein said step of removing the molding toolincludes removing the molding tool with the cast supported on themolding tool.
 43. The method of claim 41 wherein said step of removingthe molding tool comprises manually grasping a portion of the moldingtool.
 44. The method of claim 41 wherein said step of removing themolding tool is performed by unscrewing the molding tool with the castthereon from the component.
 45. The method of claim 41 wherein said stepof providing a molding tool comprises providing a rigid molding tool,and further including placing the rigid molding tool with the castsupported thereon adjacent an optical comparator, and using the opticalcomparator to analyze the cast.
 46. The method of claim 41 wherein saidstep of introducing a molding material comprises forcing moldingmaterial against an internal thread convolution in the component to forma cast of the thread convolution.
 47. The method of claim 41 whereinsaid introducing step comprises forcing the molding material intointimate contact with the internal form of the component.
 48. The methodof claim 47 wherein said forcing step includes moving a pressure memberat least partially into the passage in the molding tool to force themolding material through the passage and out of the molding tool intointimate contact with the internal form of the component.
 49. The methodof claim 41 wherein said step of introducing a molding materialcomprises directing molding material out of the molding body through aplurality of circumferentially spaced passages in the molding body. 50.A tool for making a cast of an internal form that at least partiallydefines a cavity in a component, said tool comprising: a body having afirst portion adapted to be inserted into the cavity; said body having asecond portion with a first opening therein, said second portion adaptedto at least partially reside outside of the cavity when said firstportion is inserted in the cavity; a passageway that extends from saidfirst opening to a second opening in said body with said second openingbeing within the cavity after said first end portion of said body isinserted into the cavity; and a pressure member for applying pressure toa molding material introduced into said passageway through said firstopening, wherein said body and said cast can be removed from said cavitywithout disassembling said body.
 51. The tool of claim 50 wherein saidpressure member is a plunger adapted to be inserted into said passagewaythrough said first opening to force the molding material through saidsecond opening into the cavity.
 52. A tool as set forth in claim 51wherein said body and said pressure member have threads for enablingscrewing of said pressure member at least partially into saidpassageway.
 53. The tool of claim 50 comprising a collar associated withsaid body and adapted to be manually grasped to remove the tool, and thecast thereon, from the cavity by unscrewing after the cast has beencompleted.
 54. The tool of claim 50 where said first portion is adaptedto form a cast of an internal form that at least partially includes athread convolution.
 55. The tool of claim 50 wherein said body is rigidenough to support properly the cast on an analytical instrument, such asan optical comparator, and said body has portions adapted to engage oneor more supports associated with the analytical instrument.
 56. The toolof claim 50 wherein said body is a generally cylindrical body andwherein said second portion of said body is axially closed, said secondopening being axially spaced from said second portion.
 57. The tool ofclaim 50 where said body if formed as a single-piece.
 58. A tool as setforth in claim 50 wherein said passageway includes a plurality ofcircumferentially spaced passages and said second opening includes aplurality of circumferentially spaced apertures.